The invention relates to a headrest support and, more particularly, to a headrest support that supports a headrest at an upper end of a seatback.
As this type of headrest support, a headrest support shown in FIG. 34 is conventionally known.
A headrest stay 1 is a rod-like body protruded from a bottom surface of a headrest that is supported above a seatback. Wedge-shaped height adjustment grooves 1a are formed on a side surface of the headrest stay 1.
A headrest support 2 has a tube body 3 that is formed into a tubular shape into which the headrest stay 1 can be inserted, and that is received and supported by a not-shown square pipe-made receptacle tube fixed by welding to a frame of the seatback, and a metal-made lock plate 4 that is inserted into a portion of the tube body 3 that is closer to an upper end thereof in a direction perpendicular to the headrest stay 1.
The lock plate 4 has a through-hole 4a that is elongated so as not to impede insertion of the headrest stay 1. An end of the lock plate 4 is provided with a push-in operating portion 4b that is integrally formed from resin.
The tube body 3 is provided with springs 5, 5 that contact the push-in operating portion 4b and urge the push-in operating portion 4b in such a manner as to push it out. In order to prevent the lock plate 4 from falling apart despite reaction forces from the springs, a stopper pin 6 is inserted into the tube body 3 from above, extending in a direction perpendicular to the direction of insertion of the lock plate 4.
A slit 4c for insertion of the stopper pin 6 is formed on the side of the lock plate 4. The stopper pin 6 and the slit 4c restrict the movable range of the lock plate 4.
The movable range of the lock plate 4 has a positional relationship that when the lock plate 4 is pushed in against the springs 5, 5, the lock plate 4 does not interfere, with the headrest stay 1, and that when the lock plate 4 is pushed out by the springs 5, 5, an edge portion of the through-hole 4a slightly interferes with the headrest stay 1.
That is, during a normal stable state, the lock plate 4 is in a positional relationship that the lock plate 4 interferes with the headrest stay 1, and thus engages with a height adjustment groove 1a. When a push-in operation is performed by using the push-in operating portion 4b, the engagement is discontinued so that the headrest stay 1 becomes movable up and down.
An outer peripheral surface of the tube body 3 is provided with a generally rectangular tongue piece that is formed by forming a generally squared U-shaped groove, and that has, at its distal end side, a protrusion protruded outwards, and that has flexibility substantially in a direction of a diameter of the tube body 3. When the tube body 3 is placed in the receptacle tube, the protrusion formed on the distal end side of the tongue piece is pressed against an inner peripheral surface of the receptacle tube so as to prevent the tube body from clattering against the receptacle tube.
The above-described conventional headrest support has the following problems.
First, when the tube body is placed in the receptacle tube, an upper end site of the tube body is pressed against an opening end portion of the receptacle tube. Therefore, if an impact occurs on the headrest in a direction of a height, the impact cannot be absorbed.
Second, since the generally rectangular tongue piece formed in the outer peripheral surface of the tube body 3 is supported only at its lower side by the tube body, the tongue piece cannot be provided with a sufficient strength, and is poor in durability.
Third, during assembly of the headrest support, the headrest stay 1 must be inserted into the tube body 3 while the lock plate 4 is being pressed against the tube body 3. Thus, the assembly workability is not good.
The invention has been accomplished in view of the aforementioned problems. It is an object of the invention to provide a headrest support that is capable of absorbing an impact occurring on the headrest in a direction of a height, and that has a sufficient strength and allows an improvement in assembly workability.
To achieve the aforementioned object, the invention has a construction including: a tube body that is inserted into and supported by a receptacle tube disposed in a seatback, and that retains a headrest stay inserted therein, and that allows an adjustment of a height of the headrest stay; and a spring structure that is protruded from a distal end side of the tube body toward an opening end portion of the receptacle tube, and that urges the distal end side of the tube body to move away from the opening end portion of the receptacle tube, and that urges the distal end side of the tube body to move away from the opening end portion of the receptacle tube when the tube body is pushed down to a side; of the receptacle tube.
In the thus-constructed invention, the tube body is inserted in and supported by the receptacle tube disposed in the seatback, and supports the headrest stay inserted therein, and adjusts the height of the headrest stay.
When the tube body is pushed down to a side of the receptacle tube, the spring structure protruded from the distal end side of the tube body toward the opening end portion of the receptacle tube urges the distal end side of the tube body to move away from the opening end portion of the receptacle tube. Therefore, if impact occurs on the headrest in the direction of its height, the impact is absorbed by the spring structure.
The tube body needs merely to be a tube body that is inserted into and supported by the receptacle tube disposed in the seatback, and that retains the headrest stay inserted therein, and that allows adjustment of the height of the headrest stay. For example, the tube body may be a tube body having a retaining hole capable of retaining the headrest stay while orienting the headrest stay in a direction of an axis thereof, and a lock piece retaining hole that allows the lock piece to be inserted thereinto from a side opposite from the height adjustment groove, and that allows the lock nail to be advanced and withdrawn in a direction of insertion.
The spring structure needs merely to be a spring structure that is protruded from a distal end side of the tube body toward the opening end portion of the receptacle tube, and that urges the distal end side of the tube body to move away from the opening end portion of the receptacle tube when the tube body is pushed down to a side of the receptacle tube. The spring structure may be a resin spring formed integrally with the tube body, or may be a spring structure that urges a member formed separately from the tube body by means of a spring or the like, etc.
In the former case, the resin spring is not restricted in shape in a viewpoint that the resin spring needs merely to be able to urge the distal end side of the tube body to move away from the opening end portion of the receptacle tube when the tube body is pushed down to the side of the receptacle tube. That is, the resins spring may be a resin spring that has a ring shape and is deformable in a predetermined direction, or may be a resin spring that has an arm having a flexibility in a predetermined direction, etc.
As an example of the construction in which an arm having a flexibility as-mentioned above is provided, a first resin arm connecting a plurality of positions facing the receptacle tube and a second resin arm extending in a plurality of directions from a central portion of the first arm toward the opening end portion of the receptacle tube may be formed in the tube body. In this example, if an impact occurs in the direction of the height, the impact can be absorbed by causing the first resin arm and the second resin arm contacting the opening end portion to bend in the direction of the height.
In this case, it is also possible to provide the spring structure with an additional function, such as, a function of restricting rotation of the tube body, or the like.
If, as an example of the construction in the aforementioned case, a stopper nail is protruded from a central portion of the first resin arm toward the opening end portion of the receptacle tube, and a stopper groove for restricting rotation of the tube body by engaging with the stopper nail is formed in the receptacle tube, rotation of the tube body can be restricted by the stopper groove receiving and engaging with the stopper nail.
Although the spring structure is provided for absorbing impact in the direction of the height, the tube body may clatter against the receptacle tube if impact occurs in a substantially horizontal direction. Therefore, it is also possible to provide the tube body with a construction for preventing such clattering.
As an example of the construction in the aforementioned case, the invention has a construction including: a tube body that is inserted into and supported by a receptacle tube disposed in a seatback, and that retains a headrest stay inserted therein, and that allows an adjustment of a height of the headrest stay; and a resin-made spring including a flexible portion that is formed between cutout grooves extending in an outer peripheral surface of the tube body substantially parallel in a direction of an axis of the tube body, and that has a flexibility substantially in a direction of a diameter of the tube body, and protrusion that is protruded outwards from the flexible portion, and that presses an inner peripheral surface of the receptacle tube while bending the flexible portion inwards when the tube body is inserted in the receptacle tube.
In the thus-constructed invention, the tube body is inserted in and supported by the receptacle tube disposed in the seatback, and retains the headrest stay inserted therein, and adjusts the height of the headrest stay.
When the tube body is inserted in the receptacle tube, the protrusion protruded outwards from the flexible portion presses the inner peripheral surface of the receptacle tube while causing the flexible portion that is formed between the cutout grooves extending in the outer peripheral surface of the tube body substantially parallel in the direction of the axis of the tube body and that has a flexibility substantially in the direction of the diameter of the tube body to bend inwards, thereby preventing the clattering of the tube body relative to the receptacle tube.
The tube body needs merely to be a tube body that is inserted into and supported by the receptacle tube, disposed in the seatback, and that retains the headrest stay inserted therein, and that allows adjustment of the height of the headrest stay. The tube body may be constructed similarly to the tube body in the invention in accordance with claim 1.
The resin-made spring needs merely to be a resin-made spring which includes a flexible portion that is formed between cutout grooves extending in an outer peripheral surface of the tube body substantially parallel in a direction of an axis of the tube body and that has a flexibility substantially in a direction of a diameter of the tube body, and a protrusion that is protruded outwards from the flexible portion and that presses an inner peripheral surface of the receptacle tube while bending the flexible portion inwards when the tube body is inserted in the receptacle tube, and is able to prevent the tube body from clattering relative to the receptacle tube when an impact occurs in a substantially horizontal direction.
Furthermore, it is possible to provide the resin-made spring with a tapered shape that gradually becomes thinner toward the side of the receptacle tube, so as to allow the tube body to be smoothly inserted into the receptacle tube.
The resin-made spring needs merely to be a resin-made spring that is provided on the outer peripheral surface of the tube body. The resin-made spring may be a resin-made spring that is formed at a single location, resin-made springs that are formed at a plurality of locations, etc.
In the latter case, it is possible to form a resin-made spring from a predetermined location on the outer peripheral surface of the tube body and form another resin-made spring from an outer peripheral surface portion of the tube-body opposite from the aforementioned predetermined location.
Thus, the resin-made springs press the inner peripheral surface of the receptacle tube in opposite directions, so that clattering can-be effectively prevented.
Furthermore, if a plurality of resin-made springs are formed, the resin-made springs may have equal heights or different heights.
In particular, if clattering caused by impact applied in the fore-aft direction of the vehicle during braking or the like needs to be prevented, provision of the resin-made spring in the fore-aft direction of the vehicle will effectively prevents such clattering.
The tube body may also be constructed so as to allow an improvement in the working efficiency of assembly of the headrest stay.
As an example of the construction the aforementioned case, the invention has a construction including: a lock piece having a lock nail disposed at a position that faces a height adjustment groove formed on a side; face of the headrest stay; a tube body having a retaining hole capable of retaining the headrest stay while orienting the headrest stay in a direction of an axis thereof, and a lock piece retaining hole that allows the lock piece to be inserted thereinto from a side opposite from the height adjustment groove, and that allows the lock nail to be advance and withdrawn in a direction of insertion; and engagement structure that engages the lock piece and the tube body with each other and restricts a movement of the lock nail from a position of locking with the height adjustment groove toward an opening of the lock piece retaining hole; and a spring structure that presses the lock piece disposed in the lock piece retaining hole from a side of the lock nail to the headrest stay.
In the thus-constructed invention, when the lock piece is inserted from the lock piece retaining hole formed in the tube body, the lock nail, disposed at a position facing the height adjustment groove, becomes advanceable and withdrawable in the direction of insertion.
When the lock piece is engaged with the tube body by the engagement structure formed between the lock piece and the tube body, the lock nail becomes incapable of being moved from the position of locking with the height adjustment groove formed on the side surface of the headrest stay toward the opening of the lock piece retaining hole.
Therefore, the lock piece will not fall apart from the lock piece retaining hole even though the spring mechanism presses the lock piece from a deep inward side of the lock piece retaining hole toward the opening of the lock piece retaining hole.
Hence, when the headrest stay is to be inserted into the retaining hole after the lock piece is inserted into the lock piece retaining hole during an assembly process, it is not necessary to insert the headrest stay into the retaining hole while pressing the lock piece against the lock piece retaining hole.
After assembly is completed in this manner, the spring mechanism presses the lock piece in the lock piece retaining hole against the headrest stay from the side of the lock nail. Therefore, during a normal state, the lock nail is engaged with the height adjustment groove at the lock position, thereby locking the height of the headrest stay.
If the lock piece is pushed toward a deep inward side of the lock piece retaining hole, the lock nail is withdrawn from the height adjustment groove, so that it becomes possible to change the height of the headrest stay.
Then, when the lock piece is released after the headrest stay is adjusted to a desired height, the lock piece is pushed back toward the opening side by the sprig mechanism, so that the lock piece engages with the height adjustment groove again.
The headrest stay herein needs merely to be a headrest stay that has on its, side surface a height adjustment groove. The headrest support may be a headrest stay having a plurality of height adjustment grooves that are arranged in the direction of the height, or a headrest stay having a height adjustment groove that is formed only at a specific position.
Furthermore, the height adjustment groove may be a slit formed on the side surface of the headrest stay, or may be a retaining hole for retaining the lock piece, or the like.
The lock piece needs merely to be a lock piece which has a lock nail that is disposed at a position that faces the height adjustment groove formed on the side surface of the headrest stay. The lock piece may be a lock piece formed into a generally rectangular shape, or may be a lock piece formed into a frame shape or a squared U shape.
The lock nail needs merely to be a lock nail that is engageable with the height adjustment groove. The lock nail may be a lock nail protruded in the form of a pin, or may be a lock nail formed by a peripheral edge of the lock piece, or the like.
The lock piece may be a lock piece that is entirely formed from the same material. However, if the lock piece is formed from a resin or the like, the strength of the lock nail becomes insufficient although the molding of the engagement nail becomes easy. Furthermore, if the lock piece is formed from a metal or the like; the molding of the engagement nail becomes difficult although a strength of the lock nail can be secured.
Therefore, the lock piece may be a lock piece in which the lock nail and the engagement nail are formed from different materials. The lock piece may also be formed by a metal-made plate having the lock-nail, and a resin-made knob that is provided with the engagement nail and that allows the metal-made plate to be attached thereto.
Furthermore, if a resin-made engagement nail is integrally formed with the resin-made knob, it is possible to adopt, for example, a construction in which the engagement nail has a resin arm protruded to a side opposite from the opening, and a wedge-shaped protrusion formed on a distal end side of the resin arm, and in which the engagement groove restricts insertion of the wedge-shaped protrusion at the opening side of the lock piece retaining hole, and forms, at a deep inward side of the lock-piece retaining hole, a space for receiving the wedge-shaped protrusion so that the wedge-shaped protrusion is movable in the direction of insertion.
When the engagement nail is inserted into the engagement groove, the insertion of the wedge-shaped protrusion is restricted at the opening side of the lock piece retaining hole. Therefore, the wedge-shaped protrusion is displaced to the resin arm side while bending the resin arm, as the wedge-shaped protrusion moves toward the deep inward side of the lock piece retaining hole.
When the wedge-shaped protrusion reaches the deep inward side of the lock piece retaining hole, the wedge-shaped protrusion can be placed in the aforementioned spade, so that the bending of the resin arm is removed.
Therefore, the wedge-shaped protrusion can be advanced and withdrawn in the direction of insertion while it is received in the spaced.
Integral formation of the resin arm together with the resin-made knob is preferable in terms of facilitation of the molding. However, the resin arm needs merely to be a resin arm that is at least capable of bending the wedge-shaped protrusion in a displaceable manner. The resin arm may a resin arm mounted on a member formed from a different material.
If the lockpiece retaining hole is formed to be relatively large in comparison with the dimensions of the lock piece during the resin molding of the tube body, the lock piece tends to clatter, and it becomes difficult to form the lock piece retaining hole in such a manner that the lock piece can be inserted without allowing clattering.
Therefore, it is also possible to form, in the lock piece retaining hole, a slide groove that is formed substantially parallel to the direction of advancement and withdrawal of the lock piece and that receives a side end of the metal-made plate, so that the lock piece is slid along the slide groove for advancement and withdrawal in the direction of insertion.
The slide groove may be slide grooves that are formed in opposite side walls of the lock piece retaining hole for receiving opposite side ends of the metal-made plate, or may be a slide groove that is formed in one side wall of the lock piece retaining hole for receiving only one end of the metal-made plate.
The metal-made plate and the resin-made knob may be placed together into the slide groove. It is also possible to construct the lock piece so that the metal-made plate can be more easily received by the slide groove.
For example, the metal-made plate may be formed to become wider in a direction substantially perpendicular to the direction of advancement and withdrawal of the lock piece than the resin-made knob so that the metal-made plate can be slid while it is received in the slide groove.
The metal-made plate needs merely to be a metal-made plate that has at least a lock nail formed at a side opposite from the opening of the lock piece retaining hole. If metal-made plates formed into a generally squared U shape by stamping out from a metal sheet in which the recesses of squared U-shaped plate portions face each other are used, it becomes possible to reduce unwanted metal pieces that are produced during the process, in comparison with metal-made plates formed into a frame shape.
The tube body needs merely to be a tube body that has a retaining hole capable of retaining the headrest stay while orienting the headrest stay in the direction of the axis thereof, and a lock piece retaining hole that allows the lock piece to be inserted thereinto from a side opposite from the height adjustment groove and that allows the lock nail to be advanced and withdrawn in the direction of insertion. As in the cases of claims 1 and claims 2, the tube body may be a tube body in which the lock piece retaining hole is formed near an opening of the retaining hole, or may be a tube body in which the lock piece retaining hole is formed in partway of the retaining hole.
The engagement structure needs merely to be an engagement structure that engages the lock piece and the tube body with each other and restricts movement of the lock nail from the position of locking with the height adjustment groove toward the opening of the lock piece retaining hole. The engagement structure may be an engagement structure that is formed at a side of the opening of the lock piece retaining hole or a side opposite from the opening, or may be an engagement structure that is formed in the direction of height and a side face of the lock piece retaining hole, or the like.
The engagement structure needs merely to be an engagement structure that is constructed so as to be able to engage the tube body and the lock piece with each other. The engagement structure may be an engagement structure in which an engagement nail formed in the tube body is engaged with an engagement groove formed in the lock piece, or may be an engagement structure in which, conversely, an engagement nail formed in the lock piece is engaged with an engagement groove formed in the tube body, or the like.
In the latter case, it is also possible to form an engagement nail protruded from the lock piece toward a side opposite from the opening and to form an engagement groove capable of engaging with the engagement nail at the deep inward side of the lock piece retaining hole in the tube body, so that the engagement nail protruded from the lock piece toward the side opposite from the opening is engaged with the engagement groove formed at the deep inward side of the lock piece retaining hole.
The spring mechanism needs merely to be a spring mechanism that presses the lock piece in the lock piece retaining hole from the side of the lock nail to the headrest stay. The spring mechanism may be a spring mechanism in which a helical coil is interposed at the opening side between the lock piece and the tube body, or a spring mechanism in which a helical coil is disposed at a side opposite from the opening between the lock piece and the tube body, or the like.
The spring mechanism is not limited to a spring mechanism having a helical coil as mentioned above, but may also be a spring mechanism constructed by a resin-made spring structure formed integrally with the tube body, a resin-made spring structure formed integrally with the lock piece, or the like.
A user performs height adjustment of the headrest in accordance with a need after withdrawing the lock piece from the height adjustment groove. If the headrest is pushed down to the side of the seatback by inserting the headrest stay deeply into the tube body, the resin-made knob becomes positioned in a narrow gap between the headrest and the seatback.
Therefore, in order to avoid engagement of the lock piece with the height adjustment groove when the headrest is pushed down to the side of the seatback, a height adjustment groove is normally not formed at a position that faces the lock piece in that situation.
Hence, as a substitute for the height adjustment groove, a tentative engagement structure may be provided for tentatively engaging the headrest stay with the tube body when the headrest is pushed down to the side of the seatback, so that the headrest stay is tentatively engaged with the tube body to restrict movement of the headrest stay in the direction of the axis thereof.
The tentative engagement herein means engagement of the headrest stay with the tube body to such a degree that in a situation where the headrest support is installed in a vehicle, the headrest will not change in height nor clatter despite impacts caused at the time of braking or the like, and means that when a user applies a force in such a direction as to pull the headrest stay out of the tube body in order to change the height of the headrest, a disengaged state is established to allow a height change.
The tentative engagement structure needs merely to be a tentative engagement,structure that tentatively engages the headrest stay with the tube body in a situation where the headrest is pushed down to the side of the seatback. The tentative engagement structure may be a tentative engagement structure that is caused to tentatively engage the headrest stay by an operation performed by a user, or a tentative engagement structure that engages the headrest stay with the tube body without requiring an operation performed by a user.
In the latter case, the tentative engagement structure may include a tentative engagement groove formed in a side face of the headrest stay, a tentative engagement nail that tentatively engages with the tentative engagement groove to restrict movement of the headrest stay in the direction of the axis thereof, and a spring mechanism that urges the tentative engagement nail to a side of the tentative engagement groove.
Due to this construction, the tentative engagement nail is pressed outwards by the side face of the headrest stay until the tentative engagement groove reaches a position that faces the tentative engagement nail. When the tentative engagement groove reaches the position facing the tentative engagement nail, the tentative engagement nail is moved to the side of the tentative engagement groove by the force from the spring mechanism to tentatively engage with the tentative engagement groove.
It is also possible to pre-adjust the shape of the tentative engagement nail, the spring modulus of the spring mechanism, etc. so that when it is desired that the tentative engagement nail tentatively engaged with the tentative engagement groove be withdrawn from the tentative engagement groove, that is, when a user is about to change the height of the headrest, the tentative engagement can be discontinued by the user applying a force to pull the headrest away from the seatback, whereas the tentative engagement is maintained despite impacts at the time of braking or the like. The tentative engagement structure may also be constructed so that the tentative engagement can be discontinued by a user performing a predetermined operation, for example, depressing a button or the like.
In this case, the tentative engagement structure may be provided with a drive mechanism that moves the tentative engagement nail to a side of withdrawal from the height adjustment groove.
As a result, based on depression of an operating button or the like performed by a user, the drive mechanism moves the tentative engagement nail to the side of withdrawal from the height adjustment groove.
The drive mechanism may be a drive mechanism that moves the tentative engagement nail to the side of withdrawal from the height adjustment groove via a gear mechanism or the like, or may be a drive mechanism that draws a metal-made tentative engagement nail by means of an electric magnet disposed outward of the tube body, or the like.
The tentative engagement groove needs merely to be a tentative engagement groove engageable with the tentative engagement nail. The tentative engagement groove may be a tentative engagement groove formed in a shape different from that of the height adjustment groove, or may be a tentative engagement groove formed in a shape identical to that of the height adjustment groove.
In the former case, if at the distal end side of the headrest stay, a tentative engagement face formed substantially perpendicularly to the direction of insertion into the tube body is formed in the tentative engagement groove, the tentative engagement nail can be engaged with the tentative engagement face formed at the distal end side of the headrest stay substantially perpendicularly to the direction of insertion into the tube body when the tentative engagement nail is to be engaged with the tentative engagement groove, so that even if force is applied in such a direction as to pull the headrest stay out of the tube body, the tentative engagement is more likely to be maintained, and the height of the headrest is less likely to change.
On the other hand, in the latter case, if the tentative engagement groove is formed by the height adjustment groove, it becomes possible to engage the lock piece and the tentative engagement nail with the height adjustment groove in order to restrict movement of the headrest stay in the direction of the axis thereof.
Furthermore, it is also possible to provide a constriction portion, as the tentative engagement groove, which gradually becomes thinner from the distal end of the headrest stay and becomes gradually thicker toward a side of a base end thereof.
Due to this construction, as the headrest stay is inserted into the tube body, the tentative engagement nail is pressed outwards by the distal end of the headrest stay, and is then gradually pushed back inwards in accordance with the shape of the constriction portion to establish tentative engagement.